The use of explosive devices has unfortunately become commonplace in theaters of conflict. Many attacks are made on soldiers using IED's (improvised explosive devices). These weapons can be used effectively at times. While countermeasures are sometimes available, they have so far proved to not be as effective as desired particularly when convoys are moving down roads at practical speeds. IED's can be triggered by proximity devices or may be triggered remotely through the use of a signal transmitter like a cell phone. Vehicles are being designed to withstand such explosions but even they may not be effective if the explosive device is large. Additionally, explosive devices may also be effectively utilized by people as so called suicide bombers.
Explosive devices typically contain an explosive that is detonated through a chemical reaction that produces heat. In order to detonate such an explosive device, the heat which may be provided by a shock or impact, a detonator, or generated in situ by initiating the chemical reaction with enough energy that the reaction is self sustaining.
It would be desirable to provide a means for detecting an explosive device which will not detonate the device and which means can be used to quickly detect such explosive devices while moving at a substantial speed. The detection means should be capable of detecting the explosive device far enough in advance, both time wise and distance wise, to provide sufficient warning to avoid danger.
IED's are presently detected at stand-off distances using magnetics, radio frequencies, and visual clues, none of which are specific to explosives containing objects. Closer proximity detection includes explosive detectors which are not amenable to stand-off detection at convoy speeds. Air-coupled ultrasonics are being used to measure density gradients in test explosives. Thermal imaging is being used to detect personnel and chemical releases but is plagued by fluctuating background thermal clutter.
Thus, there is a need for an improved explosives detection apparatus and method.